| 摘要 |
<p>PURPOSE:To obtain an excellent characteristic for retaining polarization by using a single mode optical fiber for which a medium having anisotropy in refractive index is used as a core material thereby providing a large difference between the propagation constants of the two base modes wherein the planes of polarization intersect orthogonally with each other. CONSTITUTION:A core part 5 of a base material for a double refraction core fiber is constituted by arraying alternately a plate-like high refractive index material 6 having a refractive index n4 and a plate-like low refractive index material 7 having a refractive index n5. Double refraction is exhibited with the fiber spun from such base material if the thickness of the material 6 and the material 7 is equal approximately to the wavelength or below in the core in the fiber state. The anisotropy in dielectric constant is generated in a direction (x) and a direction (y) and the value thereof is like the equation wherein the thickness is designated as t1, t2, the dielectric constant as epsilon1, epsilon2, the wavelength as lambda, and the average dielectric strength as epsilonx, epsilony. Then the difference in the propagation constant between the prescribed modes is virtually realized.</p> |
